Question

What is the change in internal energy if 30 J of heat are released from a

system and the system does 50 J of work on its surroundings?
Use AU = Q-W.
A. 80 J
B. -80 J
C. 20 J
D. -20 J

Answer 1

Step-by-step explanation:

Given:

Q = 30J (The system did not prepare energy, but allocated)

W = + 50 J (System operation)

__________________

ΔU - ? (Change in internal energy)

ΔU = Q - W = 30 - (50) = - 20J

Answer 2

I think it would be B- -80 J